Process of forming colored images by means of aryl hydrazones of glyoxylic acid amide



Patented Sept. 14, 1948 PROCESS or FORMING COLORED IMAGES BY *MEAN'S 'GFfARYL HYDRAZONES OF V GLYGXYEIC KCID AMIDE ,Jo'hn David-Kendall and Harold Gordon .Suggate, Ilford, England, assignors to Ilford Limited,

IlfordjEnglandya hritish company No Drawing. Application May -24, 1946., Serial N0." 6'7 2;160. I'n'Great BritainlJmfe's, I945 This "invention relates to r'colour 'zphoto'graphy and particuiari to the prodded-odor coloured images in silver halide photographic emulsion layers; i i i The usual photographic i develop'ers for silver halide photographic emulsions result simply in the formation of a silver image, and if this is removed substantially no imageremains. "Certain types of developer, however, "for example pyrogallol, used in the absence of any preservative such sodium sulphite; not only 'iorm a silver image but also'a coloured imagewhich remains when the silver image is removed. 'In British Patent No. l'5;055 of 1912 there is listed a large number d-compounds which wil1-developexposed silver halide emulsions to-si1ver images and, at the same time, form a coloured image, in situ with the silver image, which can be' 'revealed by bleaching out the silver with, for example, Farmers reducer.

According to the present invention a process of colour photography includes the step of formin 'a coloured image in a'photo'graiihic emulsion layer "carryin an image in a'reduciblesilversalt by developing such image in thepresenc'eo'f a "strong "alkali and at a temperature of at least 20' "C. by means of "a compound of the general formula: V

R-'NH-N=CH-C'ONHZ where R is a substituted or, unsubstituted aromatic nucleus;'and thereafter removingre'sidual silver ands-ilver salts from the layer.

In the preferred 'procedurefia IDhOfiOgI'ZiIJhiC ele- :inent including a photographic emulsion layer "carrying an image in "a reducible silver salt is --de'veloped=by treatment with an-aqueous solution of the: said compound containing sodium hydroxidehfpotassium hydroxide, followed by removal of the residual silver and silver salts. i

The developing compounds employed according to this invention. maybe generically defined as the airy] hydrazohes of the amides of glyoxylic acid. They may be produced by various methods, for example:

(a) An aromatic amine is diazotised and added to an ice-cold ethyl alcohol solution of cyanacetic ester in the presence of sodium acetate. A precipitate or the aryl azo c'yanacetic ester usually appears, but if it does not, owing to solubility in the solvent medium, it can be thrown "down rby "the addition of sodium carbonate. This precipitate is separated, washed and dried. The-cd-ried precipitate is then hydrolysed, for example :by boiling it in two molecular equivalents ofrpotaswsium hydroxide, 6% aqueous solution, foranliour or more. The product, which is an arylfhydrazor-1e glyoigrlic amide, may then 'becrystallisedout "from the aqueous solution and is preferably recrystallised from water, aqueous ethyl alcohol or ii-claims. (cites-8a) benzene solution in the presence of decolourlsing carbon.

11)) 1th --ary1 hydrazine is-condensedwith dichl'or acetic acid and the product methylated my treatment with dimethyl sulphate, This yields themethyl ester which in turn may be converted Ito the amide by treatment with concentrated aiilmonia.

The group R may be any and or substituted aryl' group, e, 'gpa benzene, naphthalene, anthrac'ene, iph'enanthrene, or ranthra'quinone residue which may be substituted by hydroxy, :alkoxy, :hyd-roxy-alky1, :amino, "substituted amino, nitro, sulphonic or carboxylic acid groups or halogen s; "irrhusmsm' zmemod (c) aramatiaa which maydoe-:empioyed aracior example aniline, o mandip-chioranilinesrandnitroanilines, anii ines substituted with two i or @more mitro or .chlor groupsmalkoxyanilines and,p-alkylthiolanilines,

na ihthyllaminesyaminoinaphthol sulphonic acids, amino 'lanthraquinones, sulphanilic eand anthraniilicLa'cid. r Specific examplesof developing compound ac,- cordingto-thisfinventionarefihenyllhydrazon'e of glyoxylic acid amide, MJPt.

.p-Ethoxy .lp-henyl 'hydrazone o'f arriidaMQPtl'lB C.

.p Methyl-thiol M-pheny'I hy'drazone Iii glyoxylic acid arri-ideQMfPtfl'IB 'C.

Variations-n thesdbstitutionof the pheny1 (-i. egthegrou-pRi 'hasanimportant e'fieet (in -the coiour of the image obtained and some effect-won the develo-pmen't activity. The simple phenyl hydrazone' o'f-glyoxylic acid amide combinesrata high degree of development activity with-thermoiiuction of:ayel1o\v image, amisterthat rea'son is "generally-preferred.

l'hecc ilour development isoonven'iently effected by treating e photographic elementwi-thta isdluti'on of the compound in M2 to 2% -=caus-ti'c :s'o'da solutionfor a period eif 1 0 to I'5m-inute's at 2-3-30 C. However, these concentrations, times zrand temperature's are mot limitative and wide ovariations y me' made from themj-thoughzasxalreaw indie ed -a temperature above 20 is necessary.

the invention may :be' appliedto'ithefleyelopmen't of 1 any silver salt image, lit i-i's E'Of tithe gr'eatest vaflue inqthe 'form'ationo'f cdlouriimages -in siitu with si lver images developed :drom silver rchl'orid' Tiferricyanldeandehromate. :Silverbm- "mideand silver iodobromidelatent imag es domot develop so sasily with the developing a get-its :iif this invention. Q tdllowing exaimiie "iilustrates the ir-Wention: I

.glyoxylic "acid Example Photographic paper bearing a silver chloride 7 emulsion, of the type commonly known as gaslight paper, was exposed to an object and thereafter developed for 15 minutes at 30.C. in a de-.

velopin bath of the following composition:

Phenyl hydrazone of glyoxylic acid amide gm 3 Caustic soda gm 5 Water to make litre 1 The paper was then Washed, fixed in 20% hypo solution, washed again, and thereafter bathed in Farmers reducer solution. The product carried a yellow negative image of the original object.

'- The invention is of particular value in the production of colour photographs by the three-colour subtractive process where the image correspondiiig'to the record of the blue aspects of the object photographed is required to be produced as a yellow image, Moreover, by reason of the greater development activity of the developing agent of this invention for silver chloride images, as compared with silver bromide images, it is possible to process a multilayer photographic material of which one emulsion layer is silver chloride and the others silver bromide to cause development of the former without any substantial effect on the latter.

As an example of such a process the following is instanced. A multilayer photographic material is produced comprising a colourless transparent supp ort bearing in succession (i) a redsensitive silver bromide emulsion, (ii) a green- 7 sensitive silver chloride emulsion, a'yellow filter layer, and (iii) *a blue-sensitive silver bromide emulsion. The yellow filter layer is either of the type which is resistant to ordinary development conditions or, if it is discharged under such conditions the layer contains a colourless substance which'may be converted to a yellow colour (U. S.

application Serial No. 667,992, filed May 7, 1946).

' This material is exposed to a coloured object and developed so that negative'records in silver (and complementary records in silver halide) corresponding to the red, green and blue aspects of the original object are formed in layers (1), (ii) and (iii) respectively. If the yellow filter layer has been discharged :by this treatment, it is again converted to a yellow layer by themethod indicated above. The material is then exposed to white light entering through the support, thus rendering the silver halide in layers (i) and (ii) It isthen developed first in a dedevelopable. veloper accordingto this invention, producing a yellow image in layer (ii), and then with an N.N.-dialkyl-p-phenylene diamine developer containing a colour-former which combines with the oxidation product of such developer to give a blue-green image in layer (1). former is 2:4-dichlor-a-naphthol.

The material is then re-exposed with white lightfrom the front, 1. e. with light incident on layer (iii),.and developed in an N.N.-dialkyl-pphenylene. diamine developer containing a A suitable colourcolour-former yielding a magenta image, e. g.

1-p-nitrophenyl-3-methyl 5 pyrazolone. The material isthen treated with Farmers reducer, which removes the silver images, and with an agent to discharge the colour of the yellow filter layer leaving a false-colour record of the original object.

. This record is printed on to a similar photographic material and similarly processed. The

image by the method of this invention.

What we claim is:

1. A process of colour photography which includes the step of forming a coloured image in a photographic emulsion layer carrying an image in a reducible silver salt by developing such image, in the presence of a caustic alkali and at a temperature of at least 20 0., by means of a compound of the general formula Rl II-IN=CH-CO-NH2 where R is an aromatic nucleus, and thereafter removing residual silver and silver salts from the 7 layer.

2. A process of colour photography which includes the step of forming a coloured image in a. photographic emulsion layer carrying an image in a reducible silver salt by developing such image, in the presence of a caustic alkali and at a temperature of at least 20 C., by means of a compound of the general formula Where R is an aryl radical, and thereafter removing residual silver and silver salts from the layer. a

. 3. A process of colour photography which includes the step of forming a coloured image in a photographic emulsion layer carrying an image in a reducible silver salt by developing such image, in the presence of a caustic alkali and at a temperature of at least 20 0., by means of the beta-naphthyl hydrazone of glyoxylic acid amide,

and thereafter removing residual silver and silver salts from the layer.

' 4. A process of colour photography which in-' cludes the step of forming a'coloured image in a photographic emulsion layer carrying an image in a reducible silver salt by developing such image, in the presence of a. caustic alkali and at a temperature of at least 20 0., by means of the phenyl hydrazone of glyoxylic acid amide, and

thereafter removing residual silver and silver salts from the layer.

JOHN DAVID KENDALL. V HAROLD GORDON SUGGATE. 1

REFERENCES CITED The following references are of record in the 'file of this patent:

UNITED STATES PATENTS Number Name Date I 2,172,262 Schinzel Sept. 5, 1939 2,191,502 Sease et al Feb. 27, 1940 2,196,734 Marriage Apr. 9, 1940 2,210,146 Eggert et al. Aug. 6, 1940 2,262,055 Sease et a1 Nov. 11, 1941 2,295,013 Schinzel Sept. 8, 1942 2,320,418 I Eggert June 1, 1943 2,339,213 Woodward et a1. Jan. 11,1944 

